Browsing by Person "Mason, J. I."

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Detection of endogenous nandrolone in the urine of healthy volunteers by utilising a sensitive ELISA
(2005) Al-Dujaili, Emad A. S.; Mason, J. I.; Swart, P.
Recent studies report that nandrolone, a widely used anabolic steroid by athletes to enhance their performance, is produced endogenously in the humans. However, the detection of nandrolone has mainly been indicated by the measurement of its urinary metabolites (19-norandrosterone and 19-noretiocholanone). The aim of this study was to develop a sensitive and specific ELISA for nandrolone to investigate whether the parent steroid can be detected in the urine of healthy volunteers. Nandrolone antibodies were produced by immunising sheep with nandrolone-3-CMO-KLH immunogen and used with HRP-donkey anti-sheep IgG conjugate as tracer to develop the ELISA method. Cross-reactivity values of anti-nandrolone antibody with major interfering steroids including nandrolone metabolites were minimal except for testosterone (1.8%) and dihydrotestosterone (3.98%). A sensitive standard curve for nandrolone ELISA has been constructed with good reproducibility and a minimum detection limit of 12.75 pmole/L (3.5 pg/mL). The assay was evaluated for specificity, sensitivity, parallelism, accuracy and imprecision and all found to be satisfactory. The validity of the urinary nandrolone assay was confirmed by the excellent correlation between the ELISA results and those obtained by LC/MS/MS (ELISANand=1.06 LC/MS/MS Nand+0.032, R2=0.98, p<0.001). Urinary nandrolone excretion in healthy volunteers who were known not to have taken any anabolic steroids was assessed in exercising and non-exercising individuals. In non-exercising females, endogenous urinary nandrolone levels were found to range from 0.014-2.122 ng/mL (0.069-8.98 nmol/ day), and 0.017-1.291 nmol/day for exercising females. In non-exercising males, the levels ranged from 0.018-0.486 ng/mL (0.078-2.341 nmol/day), and 0.041-2.44 nmol/day for exercising males. In conclusion, a simple, rapid and sensitive ELISA method has been developed to estimate urinary excretion of nandrolone, and used for the detection of this steroid in urine. It seems likely that nandrolone as such, though at parts per billion, is excreted in the urine of healthy subjects not knowingly ingesting steroids.
Liquorice and glycyrrhetinic acid increase DHEA and deoxycorticosterone levels in vivo and in vitro by inhibiting adrenal SULT2A1 activity
(2011) Al-Dujaili, Emad A. S.; Kenyon, C. J.; Nicol, M. R.; Mason, J. I.
The mineralocorticoid effects of liquorice are mediated by the inhibitory effects of one of its active components glycyrrhetinic acid on 11_-hydroxysteroid dehydrogenase type 2. However, liquorice is reputed to have many medicinal properties and also contains a number of other potentially biologically active compounds. Here we have investigated the wider effects of oral liquorice on steroidogenesis focussing particularly on possible inhibitory effects of glycyrrhetinic acid on adrenal sulfotransferase activity. Salivary steroids were profiled by ELISA in groups of normal male and female volunteers after consuming either liquorice-containing or non-liquorice-containing confectionary for one week. Cortisol and cortisone levels reflected expected inhibition of 11_-hydroxysteroid dehydrogenase type 2 by glycyrrhetinic acid. Salivary aldosterone was decreased but deoxycorticosterone, dehydroepiandrosterone and testosterone were increased. To assess whether glycyrrhetinic acid directly affected steroidogenesis, free and conjugated steroids were measured in incubates of adrenocortical H295 cells, firstly, in the presence or absence of forskolin and secondly, with radiolabeled deoxycorticosterone or dehydroepiandrosterone. Glycyrrhetinic acid inhibited cortisone and enhanced cortisol synthesis consistent with 11_-hydroxysteroid dehydrogenase type 2 inhibition. Basal and forskolin-stimulated syntheses of deoxycorticosterone and dehydroepiandrosterone conjugates were also inhibited in a dose-dependent manner; glycyrrhetinic acid inhibited the conjugation of deoxycorticosterone and dehydroepiandrosterone with IC50 values of 7 _M. Inhibition of deoxycorticosterone and dehydroepiandrosterone conjugation was apparent within 4 h of starting glycyrrhetinic acid treatment and was not associated with changes in the expression of SULT 2A1 mRNA. SULT2A1 encodes the enzyme sulfotransferase 2A1 which is responsible for the sulfonation of deoxycorticosterone and dehydroepiandrosterone as well as pregnenolone and 17-hydroxypregnenolone in human adrenal glands. We suggest that the glycyrrhetinic acid constituent of liquorice increases circulating and thereby, salivary levels of unconjugated deoxycorticosterone and dehydroepiandrosterone by inhibiting their conjugation at source within the adrenal cortex. This effect may contribute to the mineralocorticoid actions of glycyrrhetinic acid and gives substance to claims that liquorice also has androgenic properties. 2010 Elsevier Ireland Ltd. All rights reserved.